NaturalNano has used nanotechnology to develop a type of paint that stops cellphone signals. It's done by blending particles of copper that are inserted into nanotubes, and then mixing and suspending these tiny particles into a can of paint.

NaturalNano's idea is to completely block cellphone signals with this paint, and then provide a radio filtering device that will allow wireless signals to pass through only when they re appropriate. Using this system, a theater owner could allow cellphone signals before the show or during an intermission, but completely block them during the movie. At the same time, that theater owner could still allow emergency radio communications to get through. While jamming of cellphone signals has been ruled illegal by the FCC, it's not a crime to passively prevent signals from passing through, which is exactly what NaturalNano's paint does.

Depending on your point of view, the ability to shut down all wireless communications could either be a nightmare or a dream come true, but here's hoping every theater and concert hall in the world is soon painted with this stuff.